Field
Aspects of the present invention generally relate to a control for changing a light emitting direction of an illumination device.
Description of the Related Art
Conventionally, flash imaging involving the following procedure (hereinafter, referred to as a bounce flash imaging) has been known. Specifically, light is emitted from an illumination device to a ceiling and the like, and an object is illuminated with diffused reflected light from the ceiling and the like. With the bounce flash imaging, the object can be illuminated with the light from the illumination device, not directly but indirectly, whereby the object can be depicted with soft light.
In a flash device discussed in Japanese Patent Application Laid-Open No. 2008-180913, a light emitting unit can be manually rotated and can be stopped at a predetermined angle with a click mechanism. The flash device discussed in Japanese Patent Application Laid-Open No. 2008-180913 further includes a lock mechanism in addition to the click mechanism. The lock mechanism prevents the light emitting unit from rotating beyond the predetermined angle. The light emitting unit of the flash device discussed in Japanese Patent Application Laid-Open No. 2008-180913 includes at least the click mechanism and is rotatable in the right and left direction.
In recent years, flash devices, having what is known as an auto bounce function, as discussed in Japanese Patent Application Laid-Open No. 2011-170014 and Japanese Patent Application Laid-Open No. 2009-75340, have been developed. With the auto bounce function, a light emission direction of the flash device is rotated by a drive mechanism, using a drive source such as a motor, so that the light emitting direction is automatically adjusted.
The flash device discussed in Japanese Patent Application Laid-Open No. 2009-75340 rotates a remote light emitting unit in a casing of a head unit. The flash devices discussed in Japanese Patent Application Laid-Open No. 2011-170014 and Japanese Patent Application Laid-Open No. 2008-180913 rotate a casing (hereinafter, referred to as head unit) accommodating the light emitting unit. To achieve greater user friendliness, the flash devices having the auto bounce function preferably have, in addition to the auto bounce function, a configuration allowing a user to directly hold and manually rotate the head unit.
Generally, the following counter measure is provided for abnormalities such as collision of the drive mechanism against an obstacle, and rotated manually or by the drive mechanism. More specifically, a clutch mechanism such as a slipping clutch is provided in the drive mechanism, including the motor, to protect the drive mechanism. However, the click mechanism and the lock mechanism discussed in Japanese Patent Application Laid-Open No. 2008-180913 might hinder operations of the drive mechanism and thus are preferably not provided.
However, the head unit, stopped at a predetermined angle and held only by the holding force of the clutch mechanism, is likely to have the angle changed upon receiving external force. When the resultant angle is not what is intended by the user, the object is not properly illuminated with the illumination light, and this leads to a failure imaging.
To prevent such a problem, the clutch mechanism needs to have extremely high holding force to sufficiently hold the head unit. Alternatively, the click mechanism and the lock mechanism, which hinder the operation of the drive mechanism, need to be provided. In such cases, the drive mechanism of the head unit needs to be rigid enough to bear the holding force of the clutch mechanism or the resistive force of the click mechanism. A high-output, large-size motor is required to overcome the resistive force of the click mechanism, whereby the size and the cost of the drive mechanism increase. When the lock mechanism is provided, the configuration becomes complicated considering that the locking needs to be released when the drive mechanism operates, whereby the size and the cost of the flash device increase.